Bur for treating grindstones.



G. S. WITHAM, .ln.

BUR FOR TREATING GRINDSTONES.

APPLICATION FILED AUG-l7, I917- Patentedl Feb. 5, 1918;

2 SHEETS-SHEET gnvavfioz atkol "e143 G. S. WITHAM, In.

BUR FOR TREATING GRINDSTONES. APPLICATION FILED AUGJI. 1911.

1 %55A9% v Patented Feb. 5, 1918.

2 SHEETS-SHEET 2.

eEone-E s. wrrrmrvr,.m.,;or nunsoivrnus, NEW aLonK, assreivoe-orONE-HALF mo GEORGE s. -WITHAM, se, or HUDSON EALLs, n-Ew roan.

arm .FOR TREATING snnvnsronEs.

' Specification of Letters Patent.

Patented Feb.5, rare.

Applicaflonfile'd August 17,1917. SerialNoi186fi26.

Jr, a citizen of the United States, residing at Hudson Falls, in thecounty of Washington and State of New York, have invented certain newand useful Improvements in Burs for Treating Grindstones, of which thefollowing is a specification.

In the preparation of grindstones for the manufacture of paper pulpdifliculties have been experienced in so operating the bur employed indressing the stone as to produce the desired cut or cuts in the stone asoften the teeth of the bur out too deeply into the stone or irregularincisions are made which result in lack of uniformity in the pulp.

One feature of my invention consists in providing means for regulatingthe depth of cut made by the bur. I accomplish this by providing the burwith a circular relatively smooth bearing surface of less diameter thanthe circular series of teeth with which the bur is provided. By thisconstructhat portion of the bur carrying the teeth because in this wayrings of varying thicknesses may be used and any desired depth of cutmay be obtained. In order to produce various'qualities of pulpgrindstones of different kinds must be employed and often the depth ofcut determines the quality of the pulp obtained. By providing the burwith detachable bearing-rings the same bur may be employed for producingdifferent grades of pulp, the depth of out being determined by thethickness of the ring.

My improvements are illustrated in the accompanying drawings, in which:

Figure 1 is a top plan view of a grindstone bur equipped with myimprovements,

the frame or holder for the bur being partly shown in Figs. 3 and 4:,parts being broken away inorder to better show the construe tion.

In each case the bur proper is indicated at 1 and it is provided withteeth 5 of suitable 6 construction to dress the stone. The bur may besuitably mounted in a frame or holder 10 carrying a mandrel 3, to whichthe bur may be attached in any suitable way. I provide the bur with acircular bearing 6 surface which, as will be observed by reference toFig. 1, is of less diameter than the outer periphery of the circularseries of teeth formed on the bur. This bearing surface may be producedin various ways. In 7 Figs. 1 andQ I have shown rings 2 which areattached in any suitable way to the bur or to the shaft or mandrelcarrying the bur. It is preferable however that these rings be madedetachable. In this way they can be 7 separately formed and made of anydesired diameter. It is obvious also that by the use of rings ofdifierent diameters the depth of cut may be varied on any bur and suchrings may be applied to various kinds of burs 8 without necessarilyaltering the construction of such burs. While I prefer to employseparate rings I may embody my inven tion in the construction shown inFigs. 3, 4 and 5, in which case the bearing surfaces are 8 formed in thebody of the bur as indicated at 20. In this case also the bearingsurface is circular and is of less diameter than that of the peripheryof the teeth with which the body of the bur is provided. Such bearing 9surfaces may be easily formed on various kinds of burs and. may be madeof any desired diameter.

It will be observed that while the bearing surface is of less diameterthan that of the periphery of the teeth with which the body of the buris provided, the diameter of such bearing surface is greater than thediameter at the inner ends of the teeth.

I claim as my invention: 1

1. A cylindrical bur for treating grindstones provided with a circularseries of cutting teeth onits periphery, and with a circular relativelysmooth bearing surface the diameter of which is considerably less thanthe periphery of the toothed portion of the bur but whose diameter isgreater than the diameter at the inner ends of the teeth.

9.. A cylindrical bur for treating grind stones provided with a circularseries of 1 i cuttinglteeth on 'its periphery, and with a circularrelatively smooth bearing surface on each side of the toothed portion ofthe bur the diameter of which is considerably' lO stones provided with acircular series of cutting teeth on its periphery, and with a detachablering having a relatively smooth peripheral bearing surface the diameterof which is considerably less than the periphery of the toothed portionof the bur but 1 whose diameter-is greater than the diameter at theinner ends of the teeth.

In testimony whereof, I have hereunto subscribed my name.

GEORGE S. VVITHAM, J R.

Copies of this patent may be obtained for five cents each. by addressingthe Commissioner of Patents,

. Washington, D. 0.

